A Hero for Earth: Wheeler accidentally activates his ring by saying fire offhandedly, and blasts the floor of the Geo Cruiser with it. A small fire starts, and Gi is forced to rush to extinguish it with her own ring.
Ma-Ti: Wheeler! Don't say "fire" until you mean it!
Utopia: Though produced and released in 1991, the writers and artists all still imagining street gangs as looking (and acting) like a cross between the villains in Jem and the three punks at the beginning of the 1984 film The Terminator. Apparently none of them had seen any films on inner-city gangs made after the year 1989, such as Boyz n the Hood or Do the Right Thing.
The Conqueror: Zarm's yell when Captain Planet tosses his spacecraft into a volcano is just perfect. My goodness, did Sting really ham it up.
Heat Wave: Dr. Blight's Oh, Crap! moment when she realizes her plan failed.
MAL: Someone must have broken your force-field!
Dr. Blight: Impossible! (looks back to see a huge wave rush towards her speedboat) WHAT?!
A Formula for Hate: It's obviously not supposed to be, but the nonchalant way the doctor says, "There are only a few ways to contract the virus – using drugs with needles, unprotected sex, or that blood transfusion a few years back..." without a single pause is just... priceless.
Unbearable Blightness of Being: Due to the real Dr. Blight not telling him about her plan, MAL believes Blight!Gaia's every word. Every. single. one. At one point, he's even convinced that "Blight" has gotten the Planeteers on their side.His comment? What a woman! What a doctor! What a villain! This also backfires on the real Blight spectacularly in the episode's ending.
Bug Off: Captain Planet makes a mess in Skumm's lab, happily singing his own version of "I've Been Working on the Railroad".
Jail House Flock: Captain Planet is sent to jail. It's a real episode of this series, mind you.
Hollywaste: Dr. Blight kidnaps her good twin sister Bambi and prepares to steal her identity:
Dr. Blight: Time to walk a mile in my sister's shoes.
MAL: Her shoes, maybe, but not her jeans, judging by the rate that you are eating those donuts.
(Gilligan Cut to Dr. Blight trying to put on Bambi's jeans and ripping them)
In the same episode, when Dr. Blight pulls a switch on Bambi, she engages in Bad "Bad Acting". They say "We'll get Kath Soucie to loop over" and Linka says "I hope they get this Soucie person." Extra funny because of who their voice is.
Numbers Game: while the pollution runs rampant and animals are all apparently extinct, the Planeteers, now in their 40s, have to call out Captain Planet, which starts out normal enough... Until he appears as somewhat more grouchy than years ago.
Captain Planet: By your powers combined-! (hacking cough) Alright, waddaya want now?
A Good Bomb Is Hard to Find: Hitler (with a Fu Manchu mustache, because if they didn't, they'd get in trouble with the censors and other Moral Guardians) inflicts pain on Captain Planet by staring at him.
At the end of Skumm Lord, Captain Planet gives Verminous Skumm a choice between going to jail or going to the zoo. Skumm picks the zoo because they never have any rat exhibits there and he feels that being incarcerated at the zoo could start a trend.
Hoggish Greedly's dismay at his son Junior adopting a more environment-friendly attitude at the end of Smog Hog.